21382457 has 2 divisors, whose sum is σ = 21382458. Its totient is φ = 21382456.

The previous prime is 21382453. The next prime is 21382463. The reversal of 21382457 is 75428312.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15713296 + 5669161 = 3964^2 + 2381^2 .

It is a cyclic number.

It is not a de Polignac number, because 21382457 - 2² = 21382453 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21382453) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10691228 + 10691229.

It is an arithmetic number, because the mean of its divisors is an integer number (10691229).

Almost surely, 2^21382457 is an apocalyptic number.

It is an amenable number.

21382457 is a deficient number, since it is larger than the sum of its proper divisors (1).

21382457 is an equidigital number, since it uses as much as digits as its factorization.

21382457 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 13440, while the sum is 32.

The square root of 21382457 is about 4624.1168886610. The cubic root of 21382457 is about 277.5572243538.

The spelling of 21382457 in words is "twenty-one million, three hundred eighty-two thousand, four hundred fifty-seven".